Having a rental car is very nice (or at least people with a car). As much as I didn't like bowling Knoxville in 2003, having my car then was great. I had an X-Terra at the time. 4 of us piled and and made the trek. We had 16 bowling balls and all of our luggage in the back. Needless to say it was piled to the ceiling. If I stopped too fast bags would fly into the back seat.
Being able to move around in a city is very nice though. In NM this past year, it was great that we had the rental cause we could go anywhere we wanted. When it isn't your car, it can be a pain. You have to go where and when others want to go. In 2006 in Corpus Christi, we had friends who had a passenger van. We had to go everywhere with them or stay in the town house we rented. It got old real quick.
Vegas is a town I don't know if you would need a rental unless you plan on going outside of the city. Taxis are everywhere and I would think that the hotels will have shuttles.
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